which chemical reaction be use for cooling purpose ? that also safe for human body, not effect the human body. The more it absorb heat, the more it gets cool
Google endothermic reactions. Melting ice is a safe (usually), endothermic reaction. Technically, melting ice is an endothermic process and not a reaction. I do not know how picky you are being about nomenclature. Thus, a better example would be the reaction of water with ammonium nitrate in a so-called chemical ice pack. These "ice" packs are commonly used in the care of athletes with musculoskeletal injuries at sporting events.